1. Field of the Invention
The invention relates to a photoresist composition and a resist pattern-forming method.
2. Discussion of the Background
In the field of microfabrication used to produce an integrated circuit device or the like, lithographic technology that utilizes short-wavelength radiation (e.g., KrF excimer laser light (wavelength: 248 nm) or ArF excimer laser light (wavelength: 193 nm)) has been under development in order to achieve a higher degree of integration. A photoresist material that exhibits high sensitivity, high resolution, and the like is required when using such short-wavelength radiation. A chemically-amplified photoresist composition that includes an acid-labile group-containing component and an acid generator that generates an acid upon exposure to radiation has been widely used as the photoresist material (see Japanese Patent Application Publication (KOKAI) No. 59-45439).
A photoresist composition that includes a polymer including an alicyclic group that does not have significant absorption at 193 nm in its skeleton has been known as a composition that is suitable for ArF excimer laser light having a short wavelength. A polymer that includes a spirolactone structure has been proposed as the above polymer (see Japanese Patent Application Publication (KOKAI) No. 2002-82441 and Japanese Patent Application Publication (KOKAI) No. 2002-308937). It has been suggested that a polymer that includes a spirolactone structure improves the development contrast of a photoresist composition that includes the polymer.